Date.prototype.format = function(format) {
    var o = {
        "M+" : this.getMonth()+1, //month
        "d+" : this.getDate(),    //day
        "h+" : this.getHours(),   //hour
        "m+" : this.getMinutes(), //minute
        "s+" : this.getSeconds(), //second
        "q+" : Math.floor((this.getMonth()+3)/3),  //quarter
        "S" : this.getMilliseconds() //millisecond
    }
    if(/(y+)/.test(format)) format=format.replace(RegExp.$1,
        (this.getFullYear()+"").substr(4 - RegExp.$1.length));
    for(var k in o)if(new RegExp("("+ k +")").test(format))
        format = format.replace(RegExp.$1,
            RegExp.$1.length==1 ? o[k] :
                ("00"+ o[k]).substr((""+ o[k]).length));
    return format;
}

Date.prototype.getDateStr = function(day){
    this.setDate(this.getDate()+day);//获取AddDayCount天后的日期
    var y = this.getFullYear();
    var m = this.getMonth()+1;//获取当前月份的日期
    var d = this.getDate();
    return new Date(y+"-"+m+"-"+d);
}
